Gyroscope



Aug. 19, 1952 Filed March29, 1948.

' J. F. SCHOEPPEL ETAL GYROSCOPE 3 Sheets-Sheet 2 Zhwentons attorney Patented Aug. 19, 1952 GYROSCOPE I John F. Schoeppel, Grand Rapids, Mich.,- and" Wayne A. Stone, St. Louis Park, Minn., assignors to Minneapolis-Honeywell Regulator Company, Minneapolis,-Minn., a corporation of Delaware Application March 29, 1948, Serial No. 17,693

The present invention relates to gyroscopes and more particularly to improvements in a three degree of freedom gyroscope when used as a vertical gyroscope.

Vertical gyroscopes and erection means for the same are old in the art of gyroscopic devices. The erection of such gyroscopes must be controlled-by gravity sensitive control devices in order that a true vertical operating position be maintained by the rotor of such a gyroscope. In their earliest formsfsuch' instruments or devices had limited freedom of displacement since the objects to be controlled,-particularly ships and aircraft upon whichsuch devices were mounted, were seldom'if ever subjected to displacement in either the roll or pitch direction through angles which approached the limit position of the vertical or gravitational axes during normal operation. -With the advent of high performance military and commercial aircraft in which the range of attitude positions assumed during normal operating conditions were greatly increased; the need arose for automatically controlling such aircraft or other devices during operating conditions, and it became necessary to increase the permitted range of relative angular displacement of such 1 gyroscopic devices. Thus in the modern autopilot, in which the present type of gyroscopic device is generallyused, it became necessary to follow through and control the attitude of an aircraft up to and exceeding the position of vertical bank and vertical dive or climb. The problem here was not that of erecting the gyroscope in such attitudes'since the gyroscope generally erally displaced relative to its supporting structure in such a manner that the operation of the gravitational type control device controlling the operation of the erecting motors was ,reversed',

thereby rendering 'the' erection motors ineffective to move thegyroscope rotor to its normal ve'r- I tical operating position. Attempts to overcome this defect by the use of auxiliary erecting devices or by unbalancing the gyroscope to assume a vertical position were not completely satisfactory since it required the addition of weight and equipments to an already complexstructure thereby reducing the speed of erection and sensitivity of 12 Claims." (e1. 74-5317) such devices. The present invention overcomes this defect and provides a simple method of vertical gyroscope erection as the gyroscope is started from a standstill condition during which period one of the normal erection means is usually rendered ineffective without requiring any additional structure to the gyroscope or without impairing its operation in any manner.

It is further an object of this inventionto provide a simple and effective means of rapidly erecting a vertical gyroscope.-

It is also an object of this invention to provide an improved method of erecting a vertical gyroscope during startingoperation when the operation of one of its normal erecting means is reversed and inoperative due to displacement of the rotor and its supporting ringbeyond the normal to the vertical gravitational axis which method includes decreasing the acceleration oftherotor to decrease its back torque when, the rotor is in a predetermined position and allowing the remainingerection means to erect the gyroscope'to its normal operating position as the rotor comes up to its operating speed.

It is still further an object of this invention to provide a method of erecting a vertical gyroscope from a deenergized position whose erecting means are controlled by a gravitational type control device in which the operation of one of the control devices is reversed upon starting.

It is an object of this inventionto provide a simple method of reducing the acceleration of the rotor of the gyroscope during starting operation.

Various other objects, advantages, and features of novelty which characterize our invention become apparent from a study of the following specification anddrawings wherein: I

Figure 1 is a top plan'view of the vertical gyroscope;

Figure 2 is a front elevation view of the gyroend elevation view of. the gyrocontrolling the erection of the' vertical gyroscope as described in the preferred embodiment of the invention;

Figure 5' is a schematic end elevation view of the gyroscope with the rotor and its supporting ring and control device tilted on the gimbal ring in a counterclockwise direction as viewed from the front;

Figure 6 is. a schematic ,elevation view ofthe structure shown in 1- igure'5'with the exception r 3 that the entire tructure has been rotated clockwise 120 about the support axes;

Figure 7 is a schematic elevation view of the structure shown in Figure with the exception that the entire structure is rotated 120 counterclockwise about the support axis of the gyroscope.

Figure 8 is a schematic end elevation view of the gyroscope with the rotor and its supporting ring positioned clockwise about the support ring axis as viewed from the end of this axis at which the control device is located.

Figure 9 is a schematic view of the structure of Figure 8 with the exception that the structure is positioned about the support axis of the gyroscope 120 in a clockwise direction. a

Figure 10 i a schematic elevation view of the structure of Figure 8 with the exception that the structure is positioned 120 counterclockwise about the support axis of the gyroscope from that shown in Figure 8.

The vertical gyroscope disclosed in Figures 1, 2, and 3 comprises a rotor II, a support ring i2, 3. roll erection motor [3 for processing a Cardan or gimbal ring I4, a pitch erection motor I5 for precessing the support ring l2, a control device I6 mounted on the support ring 12 for controlling the energization of the pitch erection motor I 5, a control device I! mounted on'a gimbal ring 54 for controlling the energization of the'roll erection motor 13, and a supporting or mounting structure 28. a Y

Rotor H, as shown in the Figures 1, 2 and 3, is a'cylinder with its axis 2| (shown only in Figures 5-10) extending from the ends thereof in a vertical direction and pivoted to the support ring .l2 inbearings 22 contained in the support ring l2; iRotor H is energized from an electric fmotor', spinning means I9 as shown only in schematic Figure 4; An electricmotor is shown here for simplicity but it is to be understood thatany motivating means, such as an air motor, can b'eused as long as it can be controlled as hereinafterdisclosed. The electrical connections to the rotors spinning means I9 and the necessary slip rings and pivotal lead'connections to the stationary support mounting 25 are omitted in the drawings in an effort to simplify the disclosure since such features are old and. do not add tothe present invention. Support ring 12 includes a pair of pins or shafts 23 by which support ring I2 is mounted to the gimbal ring M and is free to rotate. The axis formed by these support ring shafts 23 passes through the center of gravity of theitotal structure supported thereby which includes the rotor H and its spinning means IS, the support ring l2 and a squirrel. cagerotor ring 24 of the roll erection motor mounted on support ring. !2. Squirrel cage ring 24 is, fastened to the support ring l2 at the pointswhere the bearings 22 of the sup port rings for the rotor shaft or axis 21 are :located. This squirrel cage ring includes a semicircular section containing the squirrel cage rotor element 25 which is the rotor for the, roll erection motor. The remaining half of the ring is a' U.-shaped channel member 25 which con' forms to and fits 'aroundthe. length or the side of the rotor H. As shown in Figures 1 and 2 this squirrel "cage ring 24 is shown for simplicity as a. continuous member which is permanently connected to the support ring I2 by a nut 39 which threads one end of bearing 22. The U- shapedchannel member or section 26 although wider than the squirrel cage rotor section 25 has the. same mass and serves to counterbalance the weight of the rotor section 25 as well as stops 3? located on the gimbal ring It.

31 are positioned so that a maximum rotation cf the support ring of 160, or to either side 4 provide a more rigid construction. In order that the erection motor may apply torque to the support ring 2 in a direction normal to its plane, the support ring 12 and squirrel cage ring 2t are positioned perpendicular to one another.

Also included on the support ring [2 is the bracket 21 which is attached slightly above one shaft 23 of the support ring l2 to be movable therewith. Bracket 21 has mounted on it, at the extremity opposite the one attached to the support ring l2, control device is or mercury switch, its mounting assembly 3| and an insulated block 32 which carries on it the wiper 33 of a potentiometer 34. Bracket 21 extends through an opening 35 in the gimbal ring Hi in such a manner that mercury switch It mounted on the end thereof and also the potentiometer wiper 33 is positioned outside of gimbal ring 14. Opening 35 in the gimbal ring 14 is semicircular and sufiicient to permit movement of the bracket 21 and the apparatus mounted thereon through approximately Support ring I 2 also carries a stop arm 36 located above the opposite end of shaft or axis 23 of the support ring l2 which arm contacts fixed Stops of its centralgor neutral. position, is permitted. Thus mercury switch [6 can bepositioned ap proximately 80 either side of its neutral position and potentiometer wiper 33 is free itomove Y through an arc of approximately 160.

Mercury switch assembly 3! includes arm 43, Y

a flexible adjusting member 4! with clamps 42 attached thereto to clasp the mercuryswitch it and secure it to the flexible member 5!." Flexible. member 4! is attached at one end'to armed by a screw 43 and is bent and oifset fromthe p. arm to enable adjustment of the position of the switch I6 relative tothe arm 49. A nutand bolt connection 44 is madethrough the offset end of the adjustable member 4| and arm 45 to provide a means of making this adjustment.

Potentiometer wiper 33, which is mounted on insulating block 32 attached to bracket 21, con

tacts and rests on a potentiometer winding-i5 which is mounted on the gimbal ring l4. Wind ing 45 is annular shaped and is attached screws 48 to a similarly shaped portion 41 of the gimbal ring M which surrounds the semicircular opening 35 through which the bracket 21 extends.

The connections to wiper 33 and winding 45 are omittedhere for simplicity and are not shown in the circuit of Figure 4 since they do not comprise a part of the invention disclosed herein. The potentiometer assembly is shown here merely to indicate onexmethod of utilizing the effect of displacement of the gyroscope in which such a device is energized and supplies a signal to a controlling circuit of Jan autopilot system, in proportion to the displacement of the rotor, about the pitch axis of the gyroscope or that axis formed by engagementof support shafts,

23 with the gimbal ring l4. 7 l

Gimbal ring It is. generally rectangular in: shape and contains bearings (not shown) into which shafts 23 of support ring '12 extend,.-for- 4 mounting the support ring 12 and its associated structure and providing a meansior allowing the support ring and its structure to bepivoted. Gimbal ring [4 similarly has shafts. 5E5

by which said ring is mounted .to the main supportingstructure 20 of the gyroscope. The axes of these shafts 50 lie in the'same plane as the bearings of the gimbal ring, and shafts 23 of the support ring I2 which fit. into these hearings and are positioned perpendicularto the latter in such a manner that if projected the axis would pass through the axis 2| of the rotor. Attached to one end of gimbal ring I4 on its inside perimeter and adjacent toone of the shafts 56 is the stator field member 5| for roll axis and are always in "operativerelationship, Squirrel cage rotor:p ort1o n. of erection motor I3 is, however, free to rowith one another.

tate about the pitch axis of the gyroscope formed by shafts 23 of the support ring relative to the gimbal ring I4. 1

Squirrel cage rotor 52' of pitch erection motor I5 is annular in form and is-attached at one end of the gimbal ring I4 in a plane perpendicular to that of the gimbal ring by screws 53 to move-with gimbal ring I4. A stator field member 54 of the pitch erection motor I5 is positioned on and attached to the frame structure 20 being stationary with respect to the remaining parts of the gyroscope. Also carried at one end of gimbal ring I4 is the mercury switch assembly 55 which assembly includes the mounting lug 56, adjustable member 51. and the mercury switch I1. Lug 56 is attached to a projecting portion 60 of the gimbal ring I4 and adjustable member 51 is attached to said lug by screw 6| with a portion of the adjustable member being oifset from portion 60 to provide for the adjustment. The nut and bolt 62 connection extending through adjustable member 51 provides a means for adjusting the position of the mercury switch which is held by clamps 63, which form a .part of the adjustable member and securely mount the switch.-.

All electrical connections between the mercury switches I6 and I1 and erection motors I3 and I5 and to the. energizing source, have been omitted in all the drawings except Figure 4, for

simplicity in disclosure. Any method of connection such as slip rings can 'be used. Figure 4, however, is merely a schematic circuit drawing of the control circuit for, the erection motors and the spinning motor of the gyroscope.

Projecting from the main support 2001? the gyroscope are two upright support members .64, 65 which contain the. bearings (not shown) for the gimbal shafts 50 and provide a means for mounting and pivoting the same. Upright support member 64 which receives one ofthe shafts 56 of gimbal ring I4 at which end the roll and pitch erection motors I3 and I5 are located contains two upraised projections or stops 66 which are contacted by and limit the. movement of a projecting lug 61 carriedby the projectingportion 60 of gimbal ring ,I4 and located adjacent to the mercury switch assembly 55 carried by that ring I4v and then paralleling the shaft 50 to project through an annular .shap'ed'openi'ng H inthe upstanding support member of main sup-' port 20. The free end of this L-shaped arm 10' carries a potentiometer wiper-'12 which moves with the gimbal ring I4. Mounted 'onupright support member 65 is an annular shaped potentiometer winding 13 which isconcentric with the opening II in support 65 which is' a'ttached there- 7 to by any suitable means" "such -"as 'screws (not shown). Wiper 12is positioned in contact with winding 13 and moves withgimbal ring-'I 4'over approximately a 240 range along which winding 13 extends. Wiper 12 and winding 13 aresh'own there only to indicate means of'utilizin'g the effect of the displacement or the'gyro'scope' about its roll axis and for this reason-the connections to' these units are also omitted here sinefit is not embodied in this invention In Figure 4 are shown thefcir'cuits which control the erection system'and the energi'zation of the rotor for the vertical gyroscope which"'cir-" cuits are energized from a common source shown as conductors 14, 15; "Connected to one side of line 14 by conductor 16 are field-"structures 5I; 54 of roll erection motor I3 and pitch erection I5 respectively. 'Field structure' 5I'of 'rQlI er'ec'tion m-o'tor I3 contains two windings ll whichare on:

nected in common atone endtocGrid'uctOr 16,

Across the other extremities 'of winding 11' is" connected condenser 80' in the well known man'- ner of capacitor or split 'ph'ase' motorss Condenser 80 is not shown inF'igures'l, 2', ar"1'd 3 but such units are usually zmoun'ted"' -on"-the'base structure 20 of the gyroscopeI The ends of wind ings 11 to which condenser iifl 'is connected-ex tend to opposite terminals or contacts'not commen with one another of mercury "switch 'I1 which control device is mounted 'on 'and'movable with the gimbal ring I4. The common electrodes of this single pole double throw mercur'y switch are connected by means of cond-uctorst I; '82,"and- 83 to the opposite side of thefsourcehof' power or line 15. The energizing circuit fon roll erection motor I3 is therefore as followsi "line 14 t'o 'conductor 16, windings'11; conden'ser'SO," to one or the other uncommon contacts of mercury'switch I1, from common, electrodes 'of*.. the mercury switch I1 to conductor 8|, conductor 82", and'con-- ductor 83 to line wire 15. Since only-one pair of the contacts of the mercury switch I1 can be made at a particular instance; one of thermotor windings 11 will be connected directly across the energizing source and the other winding 11 will be connected in series with" condenser 80 and in parallel with the first'named motor winding which is, in eficct, the line-winding'.- :The flux created by these two field winding-s '11' will be displaced in phase from-one anotherproducing a rotating flux field which acts-with'the" rotor to' cause a certain direction of-z-rotationv or applied torque. Such torque or rotation is'reversed in direction when the opposite pairpf contacts'of mercury switch I1 aremadezandthe condenser 80 is connected in series with the opposite named I field winding 11 from 'thatifirstirecitedifi Field projecting portion. These stops, as best illustrated in Figure 3, permit rotation. of the gimbal ring I4 and theremaining gyroscope structure.

At the other end of gimbal ing i4. ima ed. an- L-shaped arm 10 projecting upward from the structure 54 of the pitcherection-meter.similarly comprises two windings 84 one end of each being connected in common andsaidicommon corinec tion being connected-to line;;wire"1.4'.by'conductor 16. Condenser 88'is connected across the opp osite ends of these windings 8.4 Which-in turn are connected to terminals oric'ontacts,Enot-coinmon to one another, of mercury i'switchzsilfi. whichis I mounted on support ring I2-. Condenser 88 has also been omittedfrom Figures 1, 2, and 3 for simpli'city'but isusuallymounted on base structure 20,-. The common electrodes or terminals'of the mercury switch Hi-are connected byconductors 8. .2:. and, 83 to the opposite side of the source of power or line '75. This provides an energizing; circuit fort-he pitch erection motor as followsz line wire I4, conductor I6; windings 86, condenser 88, to one or the other uncommon contacts: of mercury switch It, the common electrodes of mercury switchIG through conductor 86, to conductor 82, and conductor 83 to line wire '15. Ina manner similar to that in which, switch I! controls the circuit. to windings TI, the con tacts of themercury: switch 16' control thecircuit in which the condense 8815 connected .so'aS to connect it in series with one or the other of l the motor windings 84, and hencethe direction. of the rotating flux field in the field structure .20 Rotor motor or spinning means I9 of rotor II I isv energized from the source-of power as fol-- which governs the direction ofapplied torque.

lows: line wire I47, conductor I6, conductor 90, spinning means 19,; conductor 9!, load resistor 81, and conductor 83, to line wire I5. Spinning means I 9-is schematicallyshown in Figure 4 as an electric motor-but it, is tobe understood that other suitable motivating means, such as relay- 93, not shown in Figures 1, 2, 3, the contacts- 94, 95 of which when closed establish a'shorting circuit through conductors 96, 9'. 'to the conductors SI and 83. Thus when the contacts cc;

95 of relay 93. are closed spinningmeans I9 will be energizedin the following circuit: line wire I4, conductor 16, to conductor 90',"to spinning means I9, conductor 9i, to conductor 93, to fixed'l contact 94 of relay 93, from movable contact 95 of relay 93 to conductor- 91, and from conductor 83 to line wire I5. Relay 93 having an operating coil I00 is energized through a thermionic tube IOI from the secondary winding I02 of transformer I03, the primary winding I04 of which is energized from lines 14, I5. Thermionic tube I 0| comprises anode'I'IO, cathode I I I, and heater I 05,, and acts as a time delay device since it does 7 not become conductive immediately upon ener-v gization until heater I 05is warmed 'up. Until tube [0| is conductive, relay coil Hi0 remains deenergized and load resistance B'i'remains in *the energization circuit of the spinning means I9 as described above. Heater I05 of tube IOI is energized from an independent secondary winding I06, transformer I03, through conductors I08, I09. Relay 93 is energized through the circuit, as follows:- secondary winding I02 of transformer I03, conductor-I01,"anode I of tube IOI, cathode III to conductor H2, resistor II3 to conductor II.4,'relay coil I00, and ground-oonductor II5 to ground conductor IIB of secondarywinding I02. The energizing circuits for the spinning means I9 and direction *motors I3 and I5 are isolated from the source by disconnect switches II! in lines 14, I5. 7

Under normal operation, the gyroscope functions in a conventional manner. With switches II'I closed, spinning means I9 and roll and pitch erection motors I3 and I5 are energized through the control of the mercury circuits described above. Spinning means I9 will be normally energized with load resistor 81 shorted out of the circuit since thermionic tube IOI provides a time delay in the energization of the relay 93 only during starting operationwhen the power is first applied to said tube. Rotor I I whenonce erected to a vertical position after starting generally maintains this vertical position during normal operation with the exception of slight amounts of precession due to friction of the gyroscope or its unbalance which are continually being corrected by the erection motors. Movement of the rotor I I about the pitch axis will cause mercury-switch I6 mounted on support ring I2 to make one or the other of a set of contacts which control the energization of the pitch erection motor I5; Depending upon which direction the rotor II is tilted about the pitch axis, and consequently whichset of contacts of mercury switch I 6 are made, the fielded of pitch erection motor I5 will be energized to applytorque in a given direction to its respective rotor 52 and consequently the gimbal ring I lattached thereto. The torque applied does not cause rotation of the gimbal ring I i except when the erection motor I3 or support ring I2 is ofiset to its stops or limiting position as 'will be later noted, but rather causes precession of the support ring I2 in a direction to counteract the degree of offset or displacement. 'In the same manner, when the gyroscope is displaced about its roll axis, that is about the shafts 50 for the gimbal ring I4, mercury switch I! mounted on gimbal ring I4 will have one or the other of its said contacts made. These contacts control the energization of the roll erection motor I3 and torque will be applied to support ring I2 and rotor 25 attached thereto from the field structure Si in such direction so as to cause gimbal ring Is to precess in a direction to counteract the displacement of gimbal ring I4 about the roll axis and return gyroscope I0 to the vertical position. Here also, rotor 25 of the roll erection motor I3 which is attached to support ring lz does not actually rotate butmerely applies a torque to the support ring I2 except when gimbal ring I4 is displaced against its limit stops, as will be later noted.

The gyroscope is mounted for operation with its base or support structure 20 fastened to any desired unit with which it is to be used, such as an aircraft. The mounting position must be such that the mercury switches I6 and H or, generally, the gravity sensitive control devices, may have a normally neutral position For the present gyroscope this normal position will be such that the base structure is mounted in a normally horizontal plane, As the unit or aircraft has been displaced in its attitude, the relationship between the base 20 and the gravita:

tional axis will be similarly displaced. Rotor II, 7

however, remains in atrue vertical position due to the operation of the gravity sensitive, control devices I5, I! and the erection. motors I3,1I5 or the precessing means for .thefgyroscop'e.

potentiometers which are operated from the gimbal and support rings are similarly displaced from their relative neutral position and provide a means of supplying a signal to indic'atethis degree of displacement of the gyroscope about its respective axes which signals are usually used to control or correct the attitude of the unit The,

:91 or iairc'raftin a'manner :well known in the art of 'autopilots' and similar systems. Such systems, however, are'beyond the scope of the presentinvention .and are omitted here.

The erection ofthe gyroscope upon starting or energization isthe primary;v motive of the present invention. To explainthis operation, the actual effect of. displacement of the gyroscope or rotor under normal operation upon the rollv and pitch erection. motors I3, I .will be. considered with respect to, the .end'svof. the roll and pitch axes, thatis the support ring I2 andgimbal ring .I 4 axes,rat which the respective mercury switches I.6,,.Il -or. gravity sensitive control devices are -located.- Inthe present gyroscope, the rotor II isfdesigned to spin .in a. clockwise direction about its respective axes as. viewedfrom the top or plan viewof Figure 1. Unless the rotor isso displacedpagainst the stops of the gimbal or Cardan I4 andsupport rings I2, the torque applied from the respective erection motors I3, I5 will cause movement of the opposite ring or erecfiQIkmOtOI'iI]. thefollowing manner. With displacement -of the support ring I2 from vertical counterclockwise, as viewedwin Figure 2, the pitch erection motor I5 will be energized to provide a clockwise torque to its rotor 52; as reviewed in Figure 3, attached to gimbal ring I4 to cause precession of support ring I2 and its rotor 25 in a clockwise direction. Conversely if the displacement of support ring I2 is clockwise, the torque applied to the rotor 52 of pitch erection motor I5 mounted on gimbal ring I4 will be counterclockwise causing support 7 ring I2 to precess counterclockwise. Likewise 'when the gyroscope; is displaced fromv the vertical about its roll-axis, that is the gimbal ring, in a clockwise direction, as viewed in Figure 3, to make the contacts of its mercury switch II, the roll erection motor I3, rotor 25 of which is attached to support ring I2, will be energized to apply a torque'to support ring I2in a clockwisedirection causing gimbal ring I4 to precess in a counterclockwise direction. I 'In the same manner when the gyroscope is'displaced about its gimbal or Cardan axis in a counterclockwise direction; roll erection motor I5 will been'ergiz'ed to applytorquet'o support ring I2 in a counterclock'wise"direction jcausing, gimbal ring I4 to precess in a clockwise direction.

Should the gyroscopebe in position against itslimit stops on the support ring I2 or gimbal ring I4, the precession would not take effect and the precessing functionof the gyroscope energized to apply torque and provide the precession acts as a'common' induction motor and moves its respective rotor in the direction to which torque was applied. I ,7 e j 'In a vertical gyroscope, gravity sensitive control devices are employed to sense displacement of a gyroscope away'from'a true vertical position. Under normal operationthe gyroscope is not displaced over 90 in either direction about itsroll or pitch axes and, as a result, the gyroscope'continues to operate in its conventional manner. With the permissive range of movement of such a gyroscope about its respective axes increased beyond this point, it is possible for the operation of the gravity type control devicestoreverse when the range of displacementof 90 to either side of the neutral or vertical position occurs. Such is usually the position assumed 'by'therotor of'the gyroscope when the gyroscope has been deenergized.

10 TheFigures 5, 6, '7; 8, 9, and lo-are schematic sketches of the rotor II, support ring I2, and gimbal ring I4 withtheir respective control devices I6, I! as viewedfr'om the end-of the gimbal axes or shaft 50 where the mercury switch I! of the .gimbalri'ng I 4 is located.' Figure 5 shows the gimbal .ring. in its neutral aposition with its control device I! inoperative. Support ring I2 and its mercury switch I6 aredisplaced slightly counterclockwise .(as viewed from the left) about the pitch axis so'thatone set. of the mercury switch contactsare made. Figure 6 shows how the operation of mercuryswitch I6 which is attached to the support ring isrever'sed as the gyroscope structure is rotated approximately- 120 clockwise about the gimbal axis from the position of Figure 5. e The opposite :set of. contacts of the mercury switch.I6 are: madeas the gimbal ring I4 passes a point of displacement from the neutral ,orlevelposition. -.Similarly, Figure 7 shows ,how the operation. of the control device I6 of the supportring I2 is, reversed; from the condition ofr-Figurefi when the;gy oscope structure is displaced counterclockwise from the position of Figure 5 with the support ring I2 remaining in the same relative position to the gimbal ring I4. Figure 3 is similar to Figure 5 withthe exception that support ring I2 and its mercury switch orrgravity sensitive control device I6 is tilted;c1ockwi se (as viewed from the left) about the pitch axis while gimbal ring I4- is in a level or neutral position. Figure 9 showshowthe operation, of .the gravity sensitive control-device or mercury switch I6 is reversed from the condition of Figure 8 when gyroscope structure or the gimbal ring I4 is displaced 120 about its respective axis clockwise from the position of Figure fi with support ring I2 remaining in thesame relative position to gimbal ring I 4. Figure 10 similarly shows how the operation of mercury switch I6 mounted on support ring I4 i s reversed from the condition of Figure 8 as the gyroscope or gimbal ring I4 is moved counterclockwise approximately 120 about thegimbal axiswithsupport ring: I2 remaining in the same relative position to gimbal ring I 4. With's'uch a reversal of operation of the control device or mercury switch I6 on the support ring, the respective pitch erection motor not only is rendered inoperative forefiecting erection of the gyroscope but 'acutally energizes motor. I5 to cause precessionin the wrong direction. The operation of the mercury switch I! which is'attached to'the' gimbal ring- I4 and which controls the. roll erectionmotor I3 'isfnot similarlyaffecte'd', and the correct set of electrodesis bridged bythe mercury regardless of the amount of displacement to cause theroll erection motorto function properly and because such' movement is limited to 120 displacement from neutral in" eitherdirection as can be seen in Figures5-10. Hence only the operation of the pitch erection motor I5 can be adversely affected by displacement of the gyroscope rotor more than'90 about the roll axis.

If the' rotor of tlie gyroscope is tilted toany of the possiblepo'sitions in which theswitch I6 causes energization of the 'pitch erection motor I5 in the wrong direction, that'motor will drive the support ring I2 toward a position in which the lug 36 is against one of the stops 31, but the roll erection motor'l3 'will function normally under the control of switch IT to cause precession about the roll axis until the mercury moves to theopposite end of "the switchIBto properly energize the 'pitch 'erec'tion motor I5.

vitysensit ive switches could be substitutedfor the mercury switches l6 and IT. For instance, pendulum operated open contact switches could be employed to perform thev same function in the same way. Also, it will be understood that the described arrangement for erecting a gyroscope is applicable to any structure where freedom about one axis exceeds 90, and that the particular roll and pitch axes as described are illustrative only.

In considering this invention it should be kept in mind that the present disclosure is intended tobe illustrative only and the scope of the invention is to be determined only by the appended claims,

We claim as our invention: a a

1. In athree degree of freedom gyroscope having a rotor with a plurality of degrees of freedom and spinning means therefor, means energizing said spinning means to give rigidity to said gyroscope, erection means operative for returning said gyroscope on departure from a normally' vertical position, a plurality of gravity sensitive control devices for controlling said erection means one of which reverses in operation beyond given ranges of displacement of said rotor, means mounting said rotor for displacement in excess of said ranges wherein the rigidity of said gyroscope sets up-areaction tending to hold said rotor displaced within said excess of said ranges, and means decreasing the acceleration of said rotor under start conditions to permit one of said erection means to overcome said reaction of said gyroscope and precess said rotor to a position within said ranges of displacement.

2. In a three degree of freedom gyroscope having a rotor with a plurality of degrees of freedom normally operating in a vertical position and spinning means therefor, means energizing said spinning means to give rigidity to said gyroscope, erection means on the rolland pitch axes of said gyroscope and operative to return said rotor to a normal position, gravity sensi-'- tive control devices controlling said erection means one of which reverses in operation beyond given ranges of displacement of said rotor, means mounting said gyroscope for displacement relative to said roll and pitch axes in excess of said ranges where the rigidity of said gyroscope sets up a reaction tending to hold said rotor displaced within said excess of said ranges, relay means, time delay means controlling the energization of said relay means, means controlled by said relay means for limiting the power to said spinning means, said power limiting means operating to decrease the rotor acceleration durin starting operation, and one of said erection means being operative to overcome said reaction of said rotor during decreased acceleration to position said rotor and said reversed gravity control device within said ranges of displacement.

3. In a three degree freedom gyroscope having a rotor with a plurality of degrees of freedom and spinning means therefor, erection means for applying. torques to said gyroscopefor processing. the same into a predetermined position, gravitational type control means for controlling sai'd erection means, one of, said erection means being rendered ineffective to precess said gyroscope to said predetermined position when said gyroscope 'isso displaced on starting that the operation of one of said control means is reversed, and means reducing the accelera- 1 tion of said rotorvduring starting operation to permit the other, of said erection means to precess said gyroscope to a position where both of said erection means are equally effective.

4." ma three degree'of'freedom gyroscope having a rotor and spinnin means therefor, erection means for applying torques to said gyroscope for precessing the same into a predetermined position, gravitational type control means for controlling said erection means, one of said erection means being rendered ineffective to erect said gyroscope when said rotor is so displaced upon starting that the operation ofone of said control meansis reversed, and means automatically effective during starting of the gyroscope for preventin rapid acceleration of said positioned to the vertical axes and 90 from 'one anothenfor displacement greater than 90 from said; vertical position about 'one of said axes, and means iapplying torque to said gyroscope upon displacement for precessing said gyroscope into'said vertical position, one of said torque applyingmeansbeing reversed in operationwhen said gyroscope is displaced more than 90 from said vertical position about said one of said'axes, and means automatically effective during starting for preventing rapid acceleration ofsaid rotor to' permit the other'of said torque applying means to precess said gyroscope toward said vertical position. I

5. iIna vertical gyroscope, a rotor and spinning j means therefor, fmeans energizing said spinning means for accelerating said rotor, means mounting said rotor and said spinning means in a normallyrvertical position for displacement relative to a pitch' an'd roll axes, a first erection means mounted concentric with said pitch axis of said gyroscope, a first control device responsive to' displacement .of said rotor about said roll axis for controlling said first erection means to cause precession of said rotor about said roll axis, a second erection means mounted concentric with said roll axis of said gyroscope, a second control device responsive to displacement of said rotor about said pitch axis and attached to said mounting means for controlling said second erection means to cause precession of said rotor about said pitch axis, said mounting means providing'for displacement of said rotor and said spinning means about said roll and said pitch axes such that said second control device is displaced to a position where it cannot control the energization of said second erection means to cause precession of said rotor about said pitch axis to said normally vertical position, and means decreasing the acceleration of said rotor during starting conditions to-permitflitapid operation of said first erection means to 'precess said rotor about said roll axis 'and posit'ion said second control device in a positionwhereitcan controlt-he energizationbffsaid secondyerection "means and cause precession of said rotor about said pitch axis to said normally vertical position.

"v: i 3; Verona; gyroscope, a rotor mounted for displacement aloout a pair of perpendicular axes,

'means for rotating said rotor to .give rigidity to said gyroscopaferection means mounted con centric with eachpf said axes for creating said 7 rotor to a normalposition, a pair of'co'ntr'ol devices each one. ofwvhichis responsive to dis, placement-of said rotor from said normal position about one o'f'saidf pair of axes for controlling one of saidereotion means located on the opposite axis} to 'er'ec'i'usaid rotor about the axis inivhich said control device responds to displacement; means mounting one of said control deviceson-said gyroscope to permit displacement thereof upon starting to a position where it is ineffective to'control its associated erection means toferec't said rotor to said normal position, and means operative upon starting of said gyroscopeto retard the rotation of said rotor and permit the other of said erection means to from said spinning meansenergizing circuit, and

thermionic tube 'lneans' foricontrolling the' operation of said relay-to provide'fortime delay in theoperationofs'a'idrelay. V

9. In a three degreeo'f'freedom gyroscope hav in'g a' rotorwith a'normallyyertical spin axis and spinning means thereforgerjection means operative for returning said gyroscope on" de-' parture irom said normally vertical position, gravitational type-control means for controlling saiol erection means energizing circuit meansfor said spinning means to' a'ccelerate said rotor, means-for retarding said acceleration of said rotor including "ar'esistor and relay means, said relay means b'e'in'g adapted to selectively insert or remove said resistor from said energizing circuit of said spinning means, and time delay 'meansfor' control-lingt-hei operation of said relay means tolimit' the time, of operation of said retarding means.

10. In ai'three'degree' of freedom gyroscope having a rotor and spinning means therefor, erection means for applying a torque to said gyroscope for precessing' the same into a predetermined position, means energizing said spinning means toaccelerate said rotor, means including a relay means for retarding said acceleration of said spinning means, and time delay -meansfor controlling "said relay means toopcrate said retarding means.

11. In a device of the class described, in com bination, a rotor having a spin axis in a normally predetermined position, spinning means for said rotor, processing means automatically operable for returning said rotor of said gyroscope to said predetermined position upon departure therefrom, an electrical energizingcircuit means for said spinning means toaccelerate said-rotor, meansfor delaying full energizajtion of said spinning means, and timefclelay means for controlling the operation of said d'ew laying means to provide'gfor time delayfin the operation of said energizationdelaying means.

12. ha gyroscope, a rotor, means mounting said rotor for rotation about a's-pinaxis in a predetermined position and for displacement about a pair oi mutually perpendicular axes, precessing means for applyin torque to saidtgyroscope rotor for returning it to said predeterw mined position upon departure therefrom, electrical energizing circuit means for said spinning means to accelerate said rotor, means for retarding the acceleration of said rotor including an impedance means and switching means adapted 'tos'electively insert 'or remove said impedance-mea'ns from'said energizing circuit, and time delay means 'for controlling the operation 7 of saidswitching'means to provide for time delay in the operation of said switching means.

JOHN'F. SCHOEPPE-L. XVAYNE A. STONE.

REFERENCES CITED The following references are of record in the 'file'of this patent:

'UNITEDSTAT'ES PATENTS Number Name. Date 1 1,558,720 Thompson l Oct. 27, 1925 2,161,241,: Bates June 6, 1939 2,278,913 Carter Apr. 7, 1942 2,315,167 VonManteuifel et a1. Mar. 30,1943 2,367,465 'Kunzer Jan. '16, 1945 2,368,644

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